176 research outputs found

    Matter and physical anisotropy of ultramafites of the Barkhatny massif (Kuznetsk Alatau ridge, Western Siberia) as criteria of their mineral potential for geological prospecting works

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    A complex of petrographic, petrofabric, and paleomagnetic analyses that was carried out for rocks from an ultrabasic massif of the Barkhatnaya Mountain in the Northern part of the Kuznetsk Alatau allowed us to prove that internal anisotropy of mineral aggregates had deformation-type evolution, which indicates possible plastic exhumation of lithosphere mantle fragments into upper crust levels. Complete conformity of geophysical and petrofabric parameters points out high possibility of multistage model for obduction of ophiolite association segments proposed for this region. Taking into account specifics of minerageny for such complexes (chromite ores and noble metals, asbestos and nephrites), we offer a new technology for geological prospecting works at the stage of estimating mineral potential of such geological objects, which is based on the presence of differently oriented systems of mineral plane orientation.Проведенный нами комплекс структурно-петрологических и палеомагнитных исследований для ультрабазитов Бархатно- го массива на северном склоне Кузнецкого Алатау подтверждает, что внутренняя анизотропия минеральных агрегатов име- ла деформационную эволюцию, которая указывает на возможную пластическую эксгумацию фрагментов мантии литосферы в верхние горизонты земной коры. Полное соответствие геофизических и петроструктурных параметров отмечает высокую вероятность многостадийной обдукции фрагментов офиолитовой ассоциации, предлагаемой для этого региона. Принимая во внимание особенности минерагении (хромитовые руды и благородные металлы, асбест и нефрит) для таких комплексов мы предлагаем новые методы геологоразведочных работ на стадии оценки рудоносности геологических объектов, которые харак- теризуются дискретными вариациями пространственной ориентировки элементов текстурной анизотропии пород

    Experiments on wave turbulence : the evolution and growth of second sound acoustic turbulence in superfluid 4He confirm self-similarity.

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    We report our experiments on the formation of second sound acoustic turbulence in superfluid 4He. The initial growth in spectral amplitude follows power laws that steepen rapidly with increasing harmonic number n, corresponding to a propagating front in frequency space. The lower growth exponents agree well with analytic predictions and numerical modeling. The observed increase in the formation delay with n validates the concept of selfsimilarity in the growth of wave turbulence

    Economic potential and development prospects of small businesses in rural areas

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    The article examines the role of small business in the development of rural areas by the example of bakery production. Moreover, it demonstrates the need for the interaction of small bakery businesses with large enterprises of the industry and grain processors. The article reveals the development trends of small bakery production in rural areas. The conditions for the participation of small bakery businesses in rural areas in the development of the production of functional and specialized bread are substantiated. The article proposes the directions and mechanisms of support for small bakery production at the level of rural territories. The development of modern methods of redistribution of bakery production in proportion to the living population, measures of state support for small bakery production and expansion of the range of bread products that contribute to improving the health of the population of Russia, is the theme of this study. The object of the research is the development of small bakery production as a condition for improving the quality of life of the population in rural areas. The subject of the research is production and management relations that ensure the development of small bakery production and its impact on the quality of life of the population in rural areas.peer-reviewe

    Parametric generation of second sound in superfluid helium: linear stability and nonlinear dynamics

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    We report the experimental studies of a parametric excitation of a second sound (SS) by a first sound (FS) in a superfluid helium in a resonance cavity. The results on several topics in this system are presented: (i) The linear properties of the instability, namely, the threshold, its temperature and geometrical dependencies, and the spectra of SS just above the onset were measured. They were found to be in a good quantitative agreement with the theory. (ii) It was shown that the mechanism of SS amplitude saturation is due to the nonlinear attenuation of SS via three wave interactions between the SS waves. Strong low frequency amplitude fluctuations of SS above the threshold were observed. The spectra of these fluctuations had a universal shape with exponentially decaying tails. Furthermore, the spectral width grew continuously with the FS amplitude. The role of three and four wave interactions are discussed with respect to the nonlinear SS behavior. The first evidence of Gaussian statistics of the wave amplitudes for the parametrically generated wave ensemble was obtained. (iii) The experiments on simultaneous pumping of the FS and independent SS waves revealed new effects. Below the instability threshold, the SS phase conjugation as a result of three-wave interactions between the FS and SS waves was observed. Above the threshold two new effects were found: a giant amplification of the SS wave intensity and strong resonance oscillations of the SS wave amplitude as a function of the FS amplitude. Qualitative explanations of these effects are suggested.Comment: 73 pages, 23 figures. to appear in Phys. Rev. B, July 1 st (2001

    Ore-forming Сonditions of the Blagodat Gold Deposit in the Riphean Metamorphic Rocks of the Yenisey Ridge According to Geochemical and Isotopic Data

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    Neodymium and strontium isotopic composition and rare earth elements (REE) distribution pattern have been determined in whole rocks and minerals were separated from host metamorphic rocks and disseminated sulfide ores of the Blagodat gold deposit. Isotopic data are given to construct few isochrones that could be reflected an age of main stages of metamorphic and metasomatic alteration in rocks varieties during a successive accumulation of gold in structural traps. The significant temporal range in the forming of the studied rocks can be interpreted as an evidence of multi-stage tectonic destruction accompanying with trust-folding processes, shear deformations and development of local fracture zones that had place from the Late Riphean to Middle Paleozoic time. According to isotopic data basic ore-forming processes were realized in the relatively narrow interval from 690 to 750 Ma that correspond to a beginning of continental rifting on the western margin of Siberian craton. Chemistry and trace element distribution are closed for host and auriferous schists and mainly showed differences in the composition initial sedimentary units. The middle negative value εNd (from -14 to -16) and very high positive value εSr (from +570 to +725) are mostly corresponded to that of upper continental crust matter. The role of synchronic granite intrusions in the studied area can be only estimated due to a generation of thermal energy and crustal fluids

    Наследование и технологическое обеспечение эксплуатационных свойств изделий с покрытиями

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    The results of studies on technological assurance and performance properties of machine parts with weld and spray-coating are presented. It is shown that the parameters of state of the surface layer and the operational properties of coated parts, along with processing conditions, are determined by the peculiarities of the structure and properties of the deposited or sputtered material.Представлены результаты исследований по технологическому обеспечению эксплуатационных свойств деталей машин с наплавленным и напыленным покрытием. Показано, что параметры состояния поверхностного слоя и эксплуатационные свойства деталей с покрытиями наряду с условиями обработки определяются особенностями структуры и свойств наплавленного или напыленного материала

    Studying of the Polylactide or Polyglycylidactide Surface Layer Biodegradation in Neutral Media for the Subsequent Layered Composite Creation

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      The processes of biodegradation in phosphate buffer with pH 7.4 and 0.9 wt.% NaCl of polymer polylactide or polyglycylidactide films for the subsequent creation of a layered composite with a biodegradable layer on the basis of a nickel-free shape memory alloy TiNbTaZr were studied. The structure of the samples was determined by SEM and an optical microscope. For polylactide films the rate of biodegradation did not depend on the mass of the film. A gradual decrease in the rate of biodegradation at any mass with a similar dependence on time is noted. With an increase in the mass of films based on poly(glycolide-lactide) the rate of biodegradation increased. And even at the initial stage the dissolution rate is 2-3 times higher than in pure polylactide. On day 180, complete dissolution of the polyglycolidelactide was observed (even a precipitate was not observed) and completely entire polylactide films, however, lost  their transparency, was noted

    Метод неинвазивной оценки влияния биологически активных веществ на скорость восстановления уровня рН в мышце после предельной нагрузки с помощью 1Н МРС

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    Purpose of the study: To determine the possibility of a non-invasive evaluation of the biologically active substances (BAS) effect on the rate of a pH level restoration in a muscle after a maximum load using 1H magnetic resonance spectroscopy (MRS).Materials and methods. Creatine monohydrate and beta-alanine were taken as tested biologically active substances, used according to the manufacturer's recommendations. At the first stage, calibration curves of a pH dependence on the magnitude of chemical shifts were plotted during assigning 1H spectra of model carnosine dipeptide solutions for non-invasive determination of intramuscular pH. Further experiments were carried out on laboratory animals (mice) using a 9 T NMR spectrometer Bruker Advance III WB 400MHz WB (Bruker, Germany). In experiments on volunteers the functional test pwc170 was used for assessing the ergogenic effects of biologically active substances on rectus quadriceps femoris. The test allows to achieve the level of myocytes cytoplasm acidification with lactate, and the effectiveness of functional biologically active substances on endurance, and also the function of aerobic systems by the muscle pH rate of recovery. Detection was performed using a high-field magnetic resonance imaging scanner (Philips Healthcare, Achieva 3.0T, North Braband, The Netherlands) and two SENSE Flex-L surface ring radiofrequency coils.Results. The effect of oral intake of creatine and beta-alanine on the restoration of rectus quadriceps femoris muscle pH after an acidification of the myocytes cytoplasm with lactate was evaluated using the 1H MRS method. Reproducible results with optimal signal-to-noise ratios and width of carnosine spectral peaks were achieved in volunteers using individual protocols and 1H MRS at 3T in the quadriceps femoris. Animal experiments have highlighted the need to develop and use more accurate techniques for voxel extraction and fat suppression during in vivo 1H spectroscopy to reliably capture the chemical shifts of carnosine peaks.Conclusion. The data obtained using 1H MRS on volunteers allow us to conclude that the developed method makes it possible to non-invasively assess the effect of biologically active substances on the rate of restoration of pH level in a muscle after a critical load in real time in vivo.Цель исследования: с помощью протонной магнитно-резонансной спектроскопии (1Н МРС) определить возможность неинвазивной оценки влияния креатина и бета-аланина на скорость восстановления уровня рН в мышце после предельной нагрузки.Материал и методы. В качестве тестируемых биологически активных веществ (БАВ) были взяты креатина моногидрат и бета-аланин, применяемые согласно рекомендациям производителя. На первом этапе были построены калибровочные кривые зависимости рН от величины химического сдвига при снятии 1Н спектров модельных растворов дипептида карнозина для неинвазивного определения внутримышечного рН. Далее проводились эксперименты на лабораторных животных (мыши линии BALB/c) с использованием 9 Тл ЯМР спектрометра Bruker Advance III WB 400 МГц WB (Bruker, Germany). Следующим шагом стали эксперименты на добровольцах по отработке методики оценки эффектов БАВ на прямой четырехглавой мышце бедра. Использовался функциональный тест pwc170 в варианте степ-теста, позволяющий достичь закисления цитоплазмы миоцитов лактатом и оценить эффективность исследуемых БАВ на запас выносливости и функциональность аэробных систем по скорости восстановления уровня рН исследуемой мышцы. Дальнейшее сканирование осуществлялось с помощью высокопольного магнитно-резонансного томографа (Philips Healthcare, Achieva 3.0 Tл, North Braband, the Nederlands) и двух поверхностных кольцевидных радиочастотных катушек SENSE Flex-L.Результаты. Методом 1Н МРС было оценено влияние перорального приема креатина и бета-аланина на восстановление рН прямой четырехглавой мышцы бедра после закисления цитоплазмы миоцитов лактатом. Эксперименты с участием мелких лабораторных животных показали необходимость разработки и использования более точных методик выделения вокселя и подавления сигнала от жировой ткани при доклинической in vivo 1H спектроскопии для надежной фиксации химических сдвигов пиков карнозина. С помощью полученных для добровольцев протоколов удалось достичь воспроизводимости результатов, оптимальных соотношения сигнал/шум и ширины спектральных пиков карнозина с помощью 1H МРС при 3 Tл в прямой четырехглавой мышце бедра.Заключение. Полученные с помощью 1Н МРС данные на добровольцах позволяют сделать вывод, что разработанная методика дает возможность неинвазивной оценки влияния БАВ на скорость восстановления уровня рН в мышце после предельной нагрузки в режиме реального времени in vivo

    Self-activated ultrahigh chemosensitivity of oxide thin film nanostructures for transparent sensors

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    One of the top design priorities for semiconductor chemical sensors is developing simple, low-cost, sensitive and reliable sensors to be built in handheld devices. However, the need to implement heating elements in sensor devices, and the resulting high power consumption, remains a major obstacle for the realization of miniaturized and integrated chemoresistive thin film sensors based on metal oxides. Here we demonstrate structurally simple but extremely efficient all oxide chemoresistive sensors with similar to 90% transmittance at visible wavelengths. Highly effective self-activation in anisotropically self-assembled nanocolumnar tungsten oxide thin films on glass substrate with indium-tin oxide electrodes enables ultrahigh response to nitrogen dioxide and volatile organic compounds with detection limits down to parts per trillion levels and power consumption less than 0.2 microwatts. Beyond the sensing performance, high transparency at visible wavelengths creates opportunities for their use in transparent electronic circuitry and optoelectronic devices with avenues for further functional convergence.open181
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